The king of the Arctic is still surprisingly contaminated with environmental toxins. According to new analyses, in addition to previously detected substances, many other harmful chemicals are found in polar bears’ bodies. The high concentration of some of these substances is particularly alarming. A decrease in intoxication was expected. However, this did not occur, and in fact increased.
Almost everywhere, humans and animals are potentially exposed to the harmful chemicals that enter the food chain from the environment. Even substances that have long been banned, such as the insecticide DDT and the carcinogenic PCBs, can still be detected basically all over the world today; even in the Arctic, such long-lived organic pollutants can be found.
The substances reach the remote polar region mainly via air and ocean currents, to the detriment of the polar bears living there. Since the first studies in the 1980s, it has been known that the white giants are very heavily contaminated with environmental toxins. As a final consumer in the food chain, they consume fish, seals and other marine life that also ingested the toxins and ultimately accumulated them in their bodies.
Jonathan Martin of the University of Alberta in Edmonton and his colleagues have studied how bear pressures have evolved in recent years, using two polar bear populations from Hudson Bay and the Beaufort Sea in the Arctic Ocean as examples. To do this, they analyzed blood serum samples from animals in both groups taken at regular intervals between 1984 and 2014. The evaluation using particularly sensitive chromatographic and mass spectrometric methods revealed some surprises. In total, the scientists detected hundreds of chemicals from a total of 13 different substance classes. These included PCBs previously found in polar bears, but also a number of previously unknown PCB metabolites.
In addition, Martin and his team discovered for the first time so-called perfluorinated alkyl sulfonic acids (PFSAs) in polar bear serum, including perfluorinated alkyl ether sulfates. These substances can have a negative effect on the reproduction and development of living beings, but are still used industrially in some cases despite health concerns.
Alarmingly, the researchers found that polar bear exposure to PFSAs actually increased steadily between 1984 and 2014. Animals from the Beaufort Sea were particularly affected. The likely reason: they live closer to China’s major industrial regions, which continue to release the chemicals into the environment on a large scale. According to them, the unexpected increase in some environmental toxins in particular is a cause for concern. It shows that current regulations and bans do not go far enough: “Endangered animal species are accumulating more and more of these substances even at the outposts of the earth, such as in the Arctic Ocean,” the team states.
Heiner Kubny, PolarJournal